R1:6100906273eb

Support unlocking applications with bin/policy

Summary: Ref T603. If you get in trouble, `bin/policy unlock PHID-APPS-PhabricatorApplicationDifferential` and such can get you out now.

Test Plan: Unlocked an application.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T603

Differential Revision: https://secure.phabricator.com/D7206